When a data communications device, such as a computer, is used to communicate with another data communications device over a telephone network, the data communications devices use modems to facilitate the transmission. A modem, coupled to a transmitting data communication device, receives digital information from the transmitting data communication device and generates an analog signal that is transmitted over a telephone call over a telephone network. A modem coupled to the receiving data communications device on the other end of the telephone call receives the telephone call including the analog signal. The modem coupled to the receiving data communications device uses its modem to demodulate the digital information included in the analog signal in the telephone call for use by the receiving data communications device. For two-way communications, the receiving data communications device uses its modem to send data to the modem of the transmitting data communications device.
A telecommunications switch terminates the connection to the transmitting data communications device. That is, a telephone transmission facility, such as a line or trunk, is connected between the telecommunications switch and the modem coupled to the transmitting data communications device. The modem places telephone calls via the telephone line connected to the telecommunications switch. Similarly, the receiving data communications device is terminated at a telecommunications switch. That is, a telephone transmission facility, such as a line or trunk, is connected between the telecommunications switch and the modem coupled to the receiving data communications equipment. Although the telecommunications switch terminating the transmitting data communications device may be the same telecommunications switch terminating the receiving data communications device, it is likely that the telecommunications switches are different. In the case where the telecommunications switches are different, a connection for a telephone call is established between the two switches over a telephone network, where the connection may traverse several telecommunications switches and multiple lines and trunks. Even where the receiving and transmitting data communications equipment is terminated on the same telecommunications switch, a virtual circuit connection across a switch fabric is required for communications. The connection between the transmitting and receiving data communications devices is formed by a virtual circuit, which uses dedicated resources on each switch and trunk or line comprising the virtual circuit. The virtual circuit requires that the telecommunications switches devote resources and bandwidth to keep the connection active. However, the data transmissions between the transmitting and receiving data communications devices are typically sporadic, not always requiring all the dedicated bandwidth of the virtual circuit. Therefore, the dedication of a virtual circuit may waste valuable telecommunications resources.
Data networks do not typically require a dedicated connection between devices for communications. Packet transmission allows data communications devices to communicate over a data network by passing discrete chunks of data or packets over shared connections. Data networks alone, however, are not sufficiently available and compatible to provide the wide area communications achievable over the public switched telephone network. In particular, a typical computer user is not connected to a wide-area data network, but relies on the public switched telephone network to provide this connectivity. Large data communications users, such as Internet service providers, seek to reduce the distance between their data networks and servers and their users' computers. By reducing the distance between the data network and a user's computer, the number of telecommunications switches used for a virtual circuit is lowered, freeing up costly resources. One known method to reduce the distance between a data network and users' computers is to employ modem pools in an area in close proximity to a telecommunications switch. The modem pools receive circuit connections for telephone calls carrying data through the telecommunications switch. The modem pools terminate the modem protocols with the users' computers and concentrate the demodulated output from users into a data network. For two-way communications, input from the service provider's servers is received by the modem pool and modulated onto the appropriate circuit connections.
FIG. 1 shows such an arrangement where a modem 10 communicates with a server 20 via a modem pool 18. As shown in FIG. 1, access circuit 12 connects modem 10 to telecommunications switch 50 for placing and receiving telephone calls. Trunk circuit 16 connects modem pool 18 to telecommunications switch 50 for transmitting and receiving telephone calls. Even though modem 10 and modem pool 18 are terminated on the same telecommunications switch 50, a virtual circuit is required for data communications between these two devices. In particular, a virtual circuit is formed between access circuit 12 and the trunk circuit 16 via the switch fabric 14 of telecommunications switch 50.
Although, the modem pool solution alleviates some of the wasted resources required for a circuit connection for data communications, at least some resources through a circuit connection are still required and likely wasted. That is, the bandwidth of the virtual circuit is not fully utilized.
Therefore, a need exists for a system that reduces the amount of telecommunications resources required for transmitting and receiving a data transmission via a connection to a switched telephone network.